Israel's prime minister, Binyamin Netanyahu, yesterday distanced himself from his brother-in-law's accusation that Barack Obama is an antisemite who hates Israel.

The family back-and-forth came as King Abdullah of Jordan added to pressure on Israel over its settlements policy, demanding the international community take firm action over what he called the "red line" of Jerusalem.

Hagai Ben-Artzi, the brother of the Israeli premier's wife, said on Israeli Army Radio that the US president dislikes Netanyahu and the Israeli people because he had spent years in the church of the Reverend Jeremiah Wright, who he said is "antisemitic, anti-Israeli, and anti-Jewish." Obama once declared the fiery liberal Chicago preacher was his spiritual mentor but disavowed him during the campaign.

"As a politician running for [the] presidency he had to hide it," Ben-Artzi said, "but it comes out every time and I think we just have to say it plainly: there is an antisemitic president in America."

Ben-Artzi then reiterated that "Jerusalem is the Israeli people's capital and the capital of the state of Israel, and it is whole and united."

"Once the Americans tried to intervene in anything related to Jerusalem we told them one simple word: 'No'," he said.

Netanyahu distanced himself from the remarks, with a spokesman saying it was not the first time the two had disagreed.

"I have a deep appreciation for President Obama's commitment to Israel's security, which he has expressed many times," Netanyahu said.

In an interview, Obama said the construction plans were not helpful for the Middle East peace process but downplayed suggestion of a rift.

"Israel's one of our closest allies, and we and the Israeli people have a special bond that's not going to go away," he said on Fox News. "But friends are going to disagree sometimes."

Meanwhile, Abdullah, a close ally of the US and Britain, demanded "firm, swift, direct and effective action to stop Israel's provocative measures in Jerusalem that seek to change its identity and threaten holy sites".

"Jerusalem is a red line and the world should not be silent about Israel's attempts to get rid of Jerusalem's Arab residents, Muslims or Christians," the king told Lady Ashton, the EU foreign policy chief, according to a palace statement.

Ashton is visiting Israel, the West Bank and the Gaza Strip today before flying to Moscow to join a meeting of the Middle East Quartet: Hillary Clinton for the US, the UN's Ban Ki-Moon, Russia's foreign minister, Sergei Lavrov, and Tony Blair, the Quartet's special representative.

Abdullah's comments came a day after the worst clashes in months broke out across East Jerusalem during a "day of rage" announced by Hamas, as the Palestinian movement urged Muslims to reach the al-Aqsa mosque to protect it from an alleged Israeli takeover attempt.

Tensions soared over the rededication of the 17th century Hurva synagogue and Israel's announcement that it was building 1,600 new homes for Jewish settlers in East Jerusalem. The al-Aqsa mosque compound was reopened and a closure of the West Bank lifted yesterday.

Top US administration officials have condemned the new homes plan, with one senior adviser, David Axelrod, calling the announcement an insult to the US.

• This article was amended on 18 March 2010. The original text described Hagai Ben-Artzi as the husband of Binyamin Netanyahu's wife. He is her brother. This has been corrected.